Heretofore, in the production process of semiconductor device, for example, IC or LSI, ordinarily, a large number of IC chips are formed on a semiconductor silicon wafer and diced by dicing.
With the needs for further miniaturization and higher performance of electronic devices, further miniaturization and higher integration of IC chip mounted on the electronic device are requested, however, the high integration of the integrated circuit in the plane direction of a silicon substrate is close to the limit
As an electrical connection method from an integrated circuit in an IC chip to an external terminal of the IC chip, a wire bonding method has been heretofore widely known. In order to reduce the size of the IC chip, in recent years, a method where a through hole is provided in a silicone substrate and a metal plug, as the external terminal is connected to the integrated circuit so as to pass through the through hole (method of forming a so-called through-silicon electrode (TSV)) is known. However, according to the method of forming a through silicon-electrode alone, the needs of higher integration for IC chip in recent years as described above are not sufficiently fulfilled.
In the light of the above, a technique of improving the integration density per unit area of the silicon substrate by making the integrated circuit in IC chip multi-layered is known. However, since the multi-layered integrated circuit increases the thickness of the IC chip, reduction in the thickness of members constituting the IC chip is required. As to the reduction in the thickness of the member, for example, reduction in the thickness of the silicon substrate has been studied and is promising not only to lead to the miniaturization of IC chip but also to save labor in a through-hole producing step of the silicon substrate in the production of through-silicon electrode.
As a semiconductor silicon wafer used in a production process of semiconductor device, the semiconductor silicon wafer having a thickness from about 700 to about 900 μm is widely known. In recent years, for the purpose of miniaturization of IC chip, it has been attempted to reduce the thickness of semiconductor silicon wafer to 200 μm or less.
However, since the semiconductor silicon wafer having the thickness of 200 μm or less is very thin and thus, a member for producing semiconductor device using the semiconductor silicon wafer as a base material is also very thin, and in the case where the member is subjected to further processing or where the member is simply moved, it is difficult to support the member stably and without imparting damage to the member.
In order to solve the problem described above, a technique is known wherein a semiconductor wafer having a device provided on the surface thereof before thinning and a supporting substrate for processing is temporarily adhered to a supporting substance for processing with a silicone adhesive, a back surface of the semiconductor wafer is ground to make it thin, the semiconductor wafer is punched to provide a through-silicon electrode, and then the supporting substrate for processing is released from the semiconductor wafer (see Patent Document 1). It is described that according to the technique, resistance to grinding at the grind of back surface of the semiconductor wafer, heat resistance in an anisotropic dry etching step or the like, chemical resistance at plating and etching, smooth final release from the supporting substrate for processing and a low adherend contamination property are able to be achieved at the same time.
Also, as a method of supporting a wafer, a technique is known which is a method for supporting a wafer by a support layer system, wherein between the wafer and the support layer system, a plasma polymer layer obtained by a plasma deposition method is interposed as a separation layer, and an adhesive strength between the support layer system and the separation layer is made larger than an adhesive strength between the wafer and the separation layer so as to be easily released the wafer from the separation layer when the wafer is released from the support layer system (see Patent Document 2).
Also, a technique of performing temporary adhesion using a polyethersulfone and a viscosity imparting agent, and then releasing the temporary adhesion with heating is known (see Patent Document 3).
Also, a technique of performing temporary adhesion with a mixture composed of a carboxylic acid and an amine, and then releasing the temporary adhesion with heating is known (see Patent Document 4).
Also, a technique is known wherein a device wafer and a supporting substrate are bonded with pressure to be adhered in a state where an adhesion layer composed of a cellulose polymer and the like is heated, and then the device wafer is released from the supporting substrate by laterally sliding under heating (see Patent Document 5).
Also, an adhesion film composed of syndiotactic 1,2-polybutadiene and a photopolymerization initiator, an adhesive force of which is changed by irradiation of radiation is known (see Patent Document 6).
Further, a technique is known wherein a supporting substrate and a semiconductor wafer are temporary adhered with an adhesive composed of a polycarbonate, the semiconductor wafer is subjected to processing, and by irradiating active energy ray and then heating, the semiconductor wafer processed is released from the supporting substrate (see Patent Document 7).
Also, an adhesive tape which is composed of an adhesive layer formed from an adhesive composition comprising an energy radiation curable copolymer having an energy radiation polymerizable unsaturated group in its side chain, an epoxy resin, and a thermally active latent epoxy resin curing agent and an adhesive force of which is changed by irradiation of radiation is known (see Patent Document 8).
As a similar technique, an adhesive agent composition containing an acrylic polymer having a weight average molecular weight from 30,000 to 2,000,000 and an unsaturated hydrocarbon group, an epoxy thermosetting resin having an unsaturated hydrocarbon group, and a heat curing agent is also known (see Patent Document 9).